A Flinders University study, to be published next month in the medical journal Sleep Health, has revealed teens have been getting 40 minutes more sleep by wearing light-emitting glasses in the morning.

Researchers tested out Re-Timer glasses in a study involving 200 Year 11 students.

“By using this device, students with sleep problems were able to get an extra 40 minutes shut eye on weeknights,” Flinders University sleep psychologist Associate Professor Michael Gradisar said.

“This is a significant boost for a group of teens who would otherwise be getting through their school week feeling sleepy and unable to concentrate on their learning.”

Dr Chris Seton, a paediatric sleep physician at Sydney University’s Woolcock Institute of Medical Research, said 70 per cent of teenagers are not getting the required nine hours sleep — having a negative effect on school work, mood and personal relationships. He believes that percentage has been doubled because of increased screen time in children and teenagers.

“I have teachers saying to me ‘why are all my kids coming back from refreshing holidays looking like zombies’,” he said.

“The late bedtime sleep-ins on school holidays push the body clock later than what it would otherwise be. We get an epidemic of kids with insomnia at the start of the school year and when daylight savings comes in at the end of the year.”

Dr Seton said digital screen time is far and away the number one factor depriving teenagers of sleep. He said the bright light on the eye reduces the stimulation of melatonin — the ‘sleepy hormone’ that naturally helps us nod off at night. But he added teenagers’ hectic schedules, energy drinks and the fact staying up late is considered normal is adding to the problem.

“Kids have normalised late bed times. If 70 per cent of kids have sleep deprivation see it as normal because all their mates go to bed late,” he said.

“When we talk to teens and tell them they need nine hours sleep they look at you as if you’re a Martian — they just don’t believe you.”

Year 12 student Stephanie Baris said the transition from holidays to school this year was very difficult. “The first week of school slowly killed me, and I was exhausted,” the 17-year-old Mona Vale girl said.

“During the holidays I would get up at 9-10am and get 11 hours sleep, but now I’m up at 6.30am and getting eight hours.”

The Abbotsleigh school student has been diagnosed with delayed sleep phase disorder, meaning her body produces sleep-inducing hormone melatonin later on in the evening than what it should. She is trialling the Re-Timer glasses in the hope of getting more sleep.